Substituted phenols



Patented Apr. 29, 194i Russell L. .le Webster Groves, Mo, assignor toMoto Chemical Comp, St. Lo, him, a corporation of Delaware No Drawing.AppllcationNovember is, 1936.

Serial No. 111,250

The present invention relates to hydroxy diphenylbenzenes, specificallyto a mixture of phenols derived from the diphenylbenzenes which resultfrom the pyrolysis of benzene in the production of diphenyl, andfurthermore, to a new phenol of this series, specifically,2,4-diphenylphenol.

The object of the invention is to provide a new phenolic product of highboiling point and having an unusual number of desirable properties. Whenbenzene is subjected to pyrolysis a crystalline material is obtained,having a boiling range at atmospheric pressure between 320 and 380 C.,the major portion (about 60% of the total) having a boiling range of 360to 380 C., but.

smaller proportions have boiling points beyond 380 C. and as high as464. C. For the most part, these higher boiling products consist ofdiphenylbenzene isomers, principally the 1,4-diphenylbenzene and thel,3-diphenylbenzene, to-

gether with smaller proportions of 1,2-diphenylbenzene and compounds ofgreater complexity, that is, compounds having a greater number ofbenzene residues in the molecule and compounds having more completelycondensed ring systems. For convenience, these higher boiling productswill-be referred to hereinafter as mixed diphenyl- .benzenes.

terials such as gasoline, lubricating oils, vegetable oils and rubber.With formaldehyde they condense in the presence of acid and alkalinecatalysts to yield oil-soluble resinous materials which are especiallyuseful for the preparation.

The description which follows comprises prefer-red methods for theproduction of these phenols by hydroxylation of the hydrocarbons.

The conversion of the mixed diphenylbenzenes to phenols can beaccomplished by two general resulting compounds.

I 2. By chlorination of the mixed diphenylbenzenes and subsequentcatalytic hydrolysis of the When the conversion of the mixeddiphenylbenzenes is conducted tomonohydric phenoliccompounds by thesulfonation vmethdd, the resulting phenols are solids of relatively highmelting point. The 'monohydric phenols obtained by .the chlorinationmethod are viscous liquids at room temperature. The products obtained,by these two methods are of substantially the same composition, that is,they are predominantly hydroxy-diphenylbenzenes, but differ somewhat inphysical characteristics because of the different proportions of theirvarious isomeric constitu ents.

To prepare the monosulfonic acids of the mixed diphenylbenzenes, theprocedure is similar to that described in Patent No. 1,865,776 grantedto C. R. McCullough. The mixed diphenylbenzenes are heated in asulfonation kettle to a temperature of about C. An equal part by weightof 66 B. sulfuric acid is added slowly with vigorous agitation. Thetemperature will rise as a result of the heat of reaction. During theadditions of sulfuric acid the temperature may be permitted to rise toabout -115 C. butshould not be allowed to rise substantially beyond thistemperature. The sulfonation mixture is maintained at-this temperaturefor an additional hour while the mass is stirred. At

the end of this time the reaction is tested for completeness by adding asample of the mixture to about 50 volumes of boiling water. A clearsolution indicates absence of unreacted hy-,- drocarbons, whereas acloudy solution indicates their presence. Should test indicate that thereaction is still incomplete, the sulfonation is continued until asatisfactory test is obtained, making the conditions of sulfonationsomewhat more drastic by raising the temperature up to as high as C. ormore if necessary. The above sulfonation conditions may be varied inknown manner, by using more concentrated sulfuric acid and a lowertemperature, or by using less concentrated acid and a highertemperature. The diphenylbenzenes need not .be in a molten conditionduring the sulfonation, but should be kept well agitated throughout theheating.

From the sulfonation mixture the sulfonic acids are separated bydilution with water and crystallized from the diluted acid in the usualmanner'for recovering sulfonic acids. The crys-- tals obtained arewashed with cold water to remove adherent excess acid. Alternatively,the sulfonic acids may be recovered as their sodium salts. I

The resulting sulfonic acids are then converted to their sodium saltsand a concentrated solution thereof prepared, or, if they'were alreadyrecovered in the preceding step as the sodium salts, a concentratedsolution thereof is prepared. This solution is fed into a fusion kettlecontaining molten sodium hydroxide to which has been added a smallproportion of water and which is at a temperature of about 300 to 420 C.The exact temperature to use in the fusion is dependent to a largeextent on the particular materials being treated. The description whichfollows is for a mixture that was easily converted to phe nols, hence ifa mixture more difficult to convert to phenols is being treated thetemperature specifled-must be accordingly raised. The solution is pumpedto the sodium hydroxide melt under the surface of the melt.Approximately three molecular equivalents of alkali are employed in thereaction, therefore the solution of the sodium sulfonates is added untilthe contents of the fusion kettle approximate these proportions; Thecontents of the kettle are then maintained at a temperature of about305310 for about 6 hours and brought up to 330 C. for an hour beforeterminating the heating. The sodium sulfite formed in the reaction issubstantially insoluble in a concentrated sodium hydroxide solution andseparates out as the reaction mixture .is then transferred to a vesselcontaining approximately an equal volume of water. ,The concentratedsolution is separated from the sodium sulfite precipitate by filtration,suitably over a nickel gauze .of fine mesh. From the concentratedsolution containing the sodium salts of the phenols, together with somevexcess alkali, the phenols are separated by neutralizing the solution bycarbon dioxide, sulfur. dioxide, sulfonic acids consisting of the nextbatch to be treated or similar acidic substances.

The phenols separate out as a slurry over the residual aqueous solution,which slurry is decanted and filtered and subjected to furtherpurification, in known manner, for example, by distillation in vacuo, orby reprecipitation from alkaline solution or by crystallization frombenzene, petroleum solvents, or alcohol, inwhich solvents the phenolsare soluble. Inasmuch as the phenols are soluble in alcohol butinsoluble in water, precipitation from an alcoholic solution by watercan be used as a method of purification,

The phenols obtained b the above procedure are white crystalline orresinous solids of variable melting point, their nature varying somewhatwith the composition of the original hydrocarbon mixture from which theyare derived. By distillation in vacuum various'fractions can beseparated.

The sulfonation can be carried to beyond the monosulfonic acid stage byknown methods, in

which event the further treatment by alkali fusion yields polyhydricphenols as products. A typical procedure for the preparation of thephenols of mixed diphenylbenzenes by the method of chlorination andsubsequent hydrolysis of. the chlorinated hydrocarbons follows: v, Themixed diphenylbenzenes are chlorinated by passing chlorine thereinto inthe presence of iron whfle the reaction mass is at a temperature of toC., in the manner described in my patent, No. 1,892,398, dated December27, 1932. The amount ofchlorine combined is determined as chlorinationprogresses by noting the increase in weight of the reaction mixture.After the desired amount of chlorine has combined, the chlorination isstopped. The chlorination is carried to the point corresponding to amonochlorinated diphenylbenzene when a monohydric phenolic end-productis desired, but is carried tothe dichlorinated stage or a higher stageif dihydric or polyhydric phenolic derivatives are to be theend-products.

The chlorinated hydrocarbon is then hydrolyzed by a treatmentwithaqueous alkali under pressure. When treating a monochlorodiphenylbenzene the proportions to use are approximately 300 grams ofthe chlorinated compound to 2000 grams of a 10 percent solution ofsodium hydroxide and these proportions are charged into an autoclavewhich can be rocked to keep the mixture agitated. The autoclave isheated until the temperature reaches 360 C., it being rocked during theentire heating, and is maintained at this temperature for about fortyminutes. The autoclave is allowed to cool thereafter and the product isremoved therefrom.

The product as removed from the autoclave is heated to boiling andfiltered. The insoluble residue is heated with 1000 cc. of 10 percentsodi-- um hydroxide solution (for 300 grams of original chlorinatedhydrocarbon) until the mixture boils and is again filtered. Thefiltrates which are now alkaline are acidified with hydrochloric acidand the hydroxy compounds separate as a viscous phenols can be preparedby the' procedure which follows hereinafter. Still another alternativemethod for the production of phenols of the mixed diphenylbenzenesfollows in the method used for the production of 2,4-diphenylphenol:

2,4-diphenylaniline can be obtained by the procedure described byWardner and Lowy (J. Amer. Chem. Soc., 1932,- vol. 54, p. 2514)., bynitration of diphenylbenzene and subsequent reduction of the resultingnitro compounds.

Fifty grams of 2,4-diphenylaniline is heated" in a beaker with 270.5 cc.of concentrated hydrochloric acid until a. fine precipitate ofthehydrochloride forms. The mixture is then cooled to 510 C.

A solution of 14.3 grams of sodium nitrite in 150 cc. of water, cooled.to about 10 C., is then slowly added with stirring to the cooledmixture I or slurry containing the hydrochloride crystals.

The temperature of the reaction mixture is maintained below 10 C.Stirring is maintained-for about 20 minutes after completion of theadditions of sodium nitrite solution, after which the small quantity ofinsoluble matter is removed by filtration.

The filtered diazonium salt solution at a temperature of about 15 C. isthen added slowly with stirring to about 1 liter of boiling water.

several times with water.

The crude phenol is purified by distillation in vacuum. Its boilingpoint is about 208-221 C. at a pressure of 4 mm. of mercury. Thefraction boiling at this temperature can be further purlfied bydissolving it in caustic soda solution and reprecipitating withhydrochloric acid. Inthis purification the phenol precipitates as an oiland crystallizes when cooled with ice. The crystals can be separated byfiltration and when again distilled boil at a temperature ofapproximately 210-215 C. at a pressure of 4 mm. The melting point of thepure phenol is 90.0-90.2 C.

The hydroxy compound is also conveniently crystallized from coal-tarsolvent naphtha.

The sodium salt is very soluble in water. It

is conveniently prepare by neutralizing the pure phenol withstoichiometrical proportions of sodium hydroxide solution and recoveringthe salt by evaporation of the solution. Alternatively, the neutralizedsolution can be evaporated to a small volume and the solution can beallowedto crystallize slowly. The sodium salt is a white solid whichcrystallizes in the form of rectangular plates.

In an analogous mannerthe potassium and similar salts can be prepared.The recovery of salts which are insolublein water can be made withoutrecourse to evaporation, that is, they can be removed by filtration fromthe residual liquid.

3 phenylbenzenes obtained by the hydroxylation of the diphenylbenzenesresulting from the pyrolysis of benzene.

3. A mixture as defined in claim 1, in which the hydroxylation has beeneffected by sulifona- 'tion of said hydrocarbons and subsequenttreatment with alkali of the resulting sulionic acids..

4. A mixture as defined in claim 2, in which the hydroxylation has beeneffected by sulfonation 0! 'said diphenylbenzenes and subsequenttreatment with alkali of the resulting sulfonic acids.

5. A mixture as defined in claim 1, in which the hydroxylation has beeneffected by chlorination of said hydrocarbons and subsequent hydrolysisof the resulting chlorinated hydrocar bons.

6. A mixture as defined in claim 2, in which the hydroxylation has beenefiected by chlorina tion 01 said diphenylbenzenes and subsequenthydrolysis of the resulting chlorinated diphe'nyl-.

benzenes.

7. A mixture as defined in claim 1 and further characterized in that thehydroxylation has been efiected by nitration of said hydrocarbons,reduc- The preferred methods of practicing the invention have beenrecited but it is to be understood that the invention is not limited toany particular method or preparing the compounds specified, exceptinsofar as such limitations are imposed by the appended claims.

Reference is made to mycopending application, Serial No. 360,902, filedOctober 12, 1940, in which is claimed subject matter disclosed but not 7claimed herein.

I claim;

1. A mixture of essentially nionohydric phenols drocarbons havingboiling points in excess of theboiling pointot diphenyl, saidhydrocarbons being produced by the pyrolysis oi benzene.

obtained by the hydroxylation of polyphenyl hy- 2. A mixture ofessentially monohydroxy-dition of the resulting nitro-compounds,diazotization of the resulting amino-compounds, and bydrolysis of theresulting diam-compounds.

8. A mixture of hydroxylated aromatic com-' pounds obtained by thehydroxylation of polyphenyl hydrocarbons having boiling points in excessof the boiling point of diphenyl, said hydrocarbons being produced bythe pyrolysis of henzene.

9. A mixture as defined in claim 8, in which the hydroxylation has beeneffected by sulfonation of said hydrocarbons and subsequent treatmentwith alkali of the resulting sulfonic acids. 10. A mixture as defined inclaim 8, in which the hydroxylation has been eflected by chlorination ofsaid hydrocarbons and subsequent hydrolysis of the resulting chlorinatedhydrocarbons.

11. A mixture as defined in claim 8, in which the hydroxylation has beenefiected by nitration of said hydrocarbons, reduction of, the resultingnitro-compounds, ,diazotization oi the resulting amino-compounds, andhydrolysis of the resulting diazo-compoimds.

12. A composition of matter consisting of a mixture of phenoliccompounds selected from the group consisting of (1) mixtures ofessentially monohydroxy diphenylbenzenes obtained by the hydroxylationof the diphenylbenzenes resulting from the-pyrolysis of benzene and (2)alkali-metal salts of said mixtures of essentially monohydroxydiphenylbenzenes.

R'Ussnm. L. JENKINS.

